611
FXUS61 KLWX 091907
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
207 PM EST Tue Dec 9 2025

.SYNOPSIS...
Canadian high pressure will drift offshore tonight. A quick
moving clipper system will pass through the Great Lakes
Wednesday. A secondary cold front will follow suit on Thursday.
Another fast moving frontal system will likely reach the area
by late Friday. A wave of low pressure may impact the area
Saturday night into Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure will glide offshore through tonight. Mid and high
level clouds will increase as a clipper system traverses the
Midwest. A few flurries could approach western Maryland during
the pre-dawn hours, but the accumulating snow is not expected to
begin until later Wednesday morning.

Low temperatures will be "milder" (relatively speaking) tonight
thanks to the increasing clouds and a steady southerly wind.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Initially focusing on the Alleghenies, the leading edge of a
trough will bring an initial rain/snow mix to start the day on
Wednesday. However, thermal profiles quickly shift over to all
snow along the western slopes of the Alleghenies. Omega fields
are fairly impressive which supports the potential for bursts of
snow showers as this trough axis passes through. Ample low-level
CAPE should result in squalls, with one wave during the late
morning and another during the mid/late afternoon into the
evening. Lift/CAPE doesn`t squarely overlap the DGZ during this
time, but that changes after midnight Wednesday night as the
column cools. Snow showers likely spill east of the Eastern
Continental Divide late Wednesday afternoon and evening, with
perhaps a dusting as far east as Cumberland-Keyser-Petersburg-
Franklin-Monterey.

Blustery winds will favor areas of blowing snow which could
lead to significant reductions in visibility and blizzard
conditions, especially along and west of the Allegheny Front
where Blizzard Warnings have been issued. Be sure to check the
forecast at weather.gov/lwx and weather.gov/lwx/winter.

Elsewhere, some light precipitation is possible along and north
of US-50, particularly closer to the Mason-Dixon Line. For
activity that does make it out to northern Maryland, early
morning thermal profiles would favor a light wintry mix. Any
accumulations would be minimal and focus over the Catoctins.
Despite ample clouds, temperatures warm through the day aided by
the breezy southerly winds around 20 to 25 mph (30 to 40 mph
across the mountains). Highs are forecast to reach the mid/upper
40s, with some low 50s possible.

Winds begin to shift to westerly by Wednesday evening as the
cold front tied to the clipper system passes through. While
clouds decrease through the night, upslope-aided snow showers
continue along and west of the Alleghenies into Thursday.
Overnight temperatures will be in the mid 20s to low 30s (teens
to mid 20s for the mountains). The blustery conditions should
lower wind chills into the single digits over the higher terrain.

Temperatures return to below average on Thursday behind the
strong cold front. The broad deep upper low across the
northeastern U.S. will also keep some clouds around. As
mentioned earlier, snow showers continue for the Alleghenies
which will further pile up at a number of spots. Conditions over
the Alleghenies should be cold and blustery as Thursday`s highs
remain in the upper teens to 20s. The gusty west-northwesterlies
drop wind chills into the single digits again. Weak high
pressure builds in for Thursday night as lows fall into the
upper teens to 20s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
A weak disturbance embedded within west-northwesterly flow aloft
will approach from the Ohio Valley on Friday. Precipitation
associated with this system will be light, but 12z guidance has
trended slightly upward with totals across our area. Plenty of cold
air will be in place at both the surface and aloft on Friday.
Temperatures may briefly climb into the mid to upper 30s, but would
quickly wet-bulb back below freezing with onset of precipitation. As
a result, precipitation type is expected to be all snow with this
system. Model soundings show the strongest lift intersecting the
dendritic snow growth zone, so a dry, fluffy, high SLR snow
character appears likely. Most solutions show snow breaking out
during the morning hours to the west of the Blue Ridge, and then
spreading to the east of the Blue Ridge by the afternoon and
evening. Snow totals will likely be on the lighter side, with most
model solutions showing between a coating and two inches. Depending
on the exact track of the system, some locations may experience no
precipitation at all. Given potential impacts to the Friday evening
commute, this system will bear watching over the coming days.

After a brief break during the daylight hours Saturday, another much
more potent disturbance will dive southeastward toward the area from
the Great Lakes. This will also be a very moisture-starved, northern
stream system. As a result, it will struggle to produce any more
than a little light precipitation, and some locations may again
receive no precipitation. It appears as though guidance is
trending a bit warmer ahead of this system, so precipitation
could occur as rain or snow, with the greatest chance occurring
Saturday night.

Strong cold advection will ensue behind that system on Sunday as
upper troughing moves overhead and a strong, 1040+ hPa high builds
southward across the Midwest. Strong northwesterly winds will usher
an Arctic airmass into the region, leading to the coldest
temperatures of the season thus far. Temperatures are forecast to
drop into the teens Sunday night (single digits in the mountains),
with wind chills in the single digits above/below zero. Cold but dry
conditions will persist through Monday as high pressure builds
overhead. Temperatures are forecast to max out in the upper 20s and
lower 30s on Monday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Mainly VFR conditions are expected through Thursday across the
area. Canadian high pressure initially centered over the region
will gradually push offshore tonight. Some elevated breezes
continue into the evening/night. Removed LLWS from the TAFs
given not much directional change with height and a steady
surface wind persisting through much of the night.

By Wednesday, southerly winds further increase ahead of a quick
moving clipper system. Some brief restrictions are possible
15Z-21Z Wednesday at northern terminals as light precip tracks
through. Otherwise, most stay dry through the day with southerly
gusts to around 20 to 25 knots. The accompanying cold front
races across the region by Wednesday evening which ushers in a
gusty west-northwesterly wind in the wake. Northwesterly
breezes remain elevated into Thursday as an upper low passes to
the north.

VFR conditions are expected Friday morning. Sub-VFR conditions
appear possible Friday afternoon into Friday evening, and then
potentially again Saturday night in association with snow. Winds are
forecast to be out of the southwest on Friday, before turning out of
the west on Saturday.

&&

.MARINE...
High pressure will push offshore tonight which aids in
southerly channeling effects. The uptick in southerly winds
continue into much of Wednesday ahead of a cold front. While
some gale-force winds are noted in the column, most gusts should
stay in the 25-30 knot range.

By Wednesday evening/night, winds shift to west-northwesterly
behind the cold front with continued advisory-caliber winds
overspreading the waters. Hazardous marine conditions continue
into Thursday as northwesterlies gust to around 20 to 25 knots.

Sub-SCA level southwesterly winds are expected on Friday. SCA
conditions appear possible within westerly flow on Saturday.

&&

.TIDES/COASTAL FLOODING...
While current tidal anomalies are around 0.25 to 0.50 feet,
expect these to rise through Wednesday in response to the shift
to southerly flow. This does bring Annapolis and possibly Havre
de Grace into Action stage. However, this is rather brief
before water levels quickly fall behind the strong clipper-type
system during subsequent days.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 7 PM this evening to 6 PM EST
     Thursday for MDZ008.
     Blizzard Warning from 10 AM Wednesday to 10 AM EST Thursday
     for MDZ509.
     Winter Weather Advisory from 4 PM Wednesday to 7 AM EST
     Thursday for MDZ510.
VA...Winter Weather Advisory from 4 PM Wednesday to 7 AM EST
     Thursday for VAZ503.
WV...Blizzard Warning from 10 AM Wednesday to 10 AM EST Thursday
     for WVZ501-505.
MARINE...Small Craft Advisory from 7 PM this evening to 6 PM EST
     Thursday for ANZ530>543.

&&

$$

SYNOPSIS...BRO/DHOF
NEAR TERM...DHOF
SHORT TERM...BRO/DHOF
LONG TERM...KJP
AVIATION...BRO/DHOF/KJP
MARINE...BRO/DHOF/KJP
TIDES/COASTAL FLOODING...LWX